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Finding the Fourth Proportional to 657.80, 986.70 and 398.60

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Solution

The fourth proportional to 657.80, 986.70 and 398.60 is: 597.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    657.80 : 986.70 = 398.60 : x
  2. Step 2: Convert to fraction form
    657.80/986.70 = 398.60/x
  3. Step 3: Cross multiply
    657.80x = 986.70 × 398.60
  4. Step 4: Simplify right side
    657.80x = 393,298.62
  5. Step 5: Solve for x
    x = 393,298.62/657.80
  6. Step 6: Final answer
    x = 597.90

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.